Why Extraterrestrial Life May Need Alien Oceans

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Scientists searching for planets where E.T. may live have homed
in on places where liquid water could exist. But a livable world
may require not just water, but oceans, a new study suggests.

A team of scientists created a computer simulation of ocean
circulation on a hypothetical
Earth-like planet. The findings show that oceans play a vital
role in establishing a habitable and stable climate, according to
the study published Sunday (July 20) in the journal Astrobiology.

"The number of planets being discovered outside our solar system
is rapidly increasing," David Stevens, an applied mathematician
at the University of East Anglia in England,
said in a statement. "This research will help answer whether
or not these planets could sustain alien life." [ 7
Huge Misconceptions About Aliens ]

The number of known, potentially habitable exoplanets in the
Milky Way galaxy has mushroomed in recent years, largely thanks
to NASA's Kepler telescope, which detects the tiny dips in
brightness of stars as planets cross in front of, or transit,
them.

Scientists calculate that as many as one in five sunlike stars
may harbor an Earth-like planet in the so-called "Goldilocks"
zone — a region around a star thought to be just right for liquid
water to exist. Researchers are now taking that a step further,
looking for water and other
signs of alien life in a planet's atmosphere.

As a result, most simulations of Earth-like planets with
habitable climates focus on their atmospheres. But now, Stevens
and his colleagues have created a simulation with an
ocean-covered planet. With their model, the researchers
investigated how changing the planet's
rotation speed affected the transportation of heat when
oceans were present.

The massive bodies of water played a major role in moderating
climate on the hypothetical planet, the researchers found.Oceans
"are beneficial because they cause the surface temperature to
respond very slowly to seasonal changes in solar heating,"
Stevens said, adding that "they help ensure that temperature
swings across a planet are kept to tolerable levels."

The oceans transported heat across the planet, which could make
more of the planet's surface habitable, the researchers said.

Many planets lie in the so-called habitable zone of their stars,
but without oceans, the surface temperatures fluctuate wildly,
the researchers said. Mars is a good example, because the planet
orbits within the sun's habitable zone, but has temperatures that
vary by 180 degrees Fahrenheit (82 degrees Celsius) over the
course of a Martian day.

Including oceans in climate models of potentially habitable alien
planets could prove essential to understanding whether any
Earth-like worlds out there could develop and sustain life, the
researchers said.